PORTLAND CEMENT CONCRETE ROADS. 
19 
Figure 5. As the offset from the tangent to the inner circular curve 
in this case will be increased by the amount of widening required, 
the length of the transition to the inner edge of the pavement will 
always be longer than the transition used on the outer edge of the 
pavement. The use of transition curves will materially increase the 
field operations of staking out the work, but it is believed their use 
is desirable on curves of from 200 to 1,000 foot radius. 
Edge of Standard Section 
Tapered Portion of Pavement 
-Center Line of Standard Section 
f?= Radius of Center Line of Standard Section of Pavement. 
PC.= Point of Curve. 
PT= Point of Tangent 
W= Width of Standard Section of Pavement. 
A - Additional Width of Pavement on Account of Curve. 
100 Feet = Length of Taper. 
N0TE>The Taper will not strictly be Tangent to the Widened 
Portion of the Curve at the PC. The Point of Tangency is 
so near the PC, however, that a slight shifting of the 
Forms at this Point during the Setting will connect the 
Taper with the Curve without any Noticeable Break. 
In no case will the Forms at the PC. have to be moved 
more than .15 Foot. 
Fig. 4. — A simple method of widening curves. 
Table of curve widening. 
Additional width of pave- 
Additional width of pave- 
Radius 
ment required for — 
Radius 
ment 
required for — 
of 
center 
of 
center 
line 
16-foot 
18-foot 
20-foot 
line 
16-foot 
18-foot 
20- foot 
curve. 
pave- 
pave- 
pave- 
curve. 
pave- 
pave- 
pave- 
ment. 
ment. 
ment. 
ment. 
ment. 
ment. 
Feet. 
Feet. 
Feet. 
Feet. 
Feet. 
Feet. 
Feet. 
Feet. 
30 
8.0 
11.0 
14.0 
125 
3.5 
4.0 
4.0 
40 
6.0 
8.0 
9.5 
150 
3.5 
3.5 
3.5 
50 
5.5 
6.5 
7.5 
175 
3.0 
3.0 
3.0 
60 
5.0 
5.5 
6.5 
200 
3.0 
3.0 
3 
70 
4.5 
5.0 
5.5 
250 
3.0 
3.0 
2.5 
80 
4.0 
4.5 
5.0 
300 
3.0 
2.5 
2.5 
90 
4.0 
4.5 
4.5 
400 
3.0 
2.5 
2.0 
100 
4.0 
4.0 
4.5 
500 
2.5 
2.5 
2.0 
